comment on

I fed your JustShift solution (a cute bit of lateral thinking :), into my benchmark and on my hardware it is a tad slower than shift&and:

C:\test>1021064
Shift&and took: 0.000000611130 seconds
justshift took: 0.000000651048 seconds
  Lookup  took: 0.000000488745 seconds
  Lookup2 took: 0.000000706896 seconds
(un)pack  took: 0.000007464467 seconds
[download]

I was a bit surprised by that as both shift & and are designated as single clock operations on my cpu. I guess the difference is in the perl operations that overlay them.

I follow your drift regarding the effect that assignment and stack handling can have on a benchmark of this nature; but the values are re-used several times through the rest of the body of the inner loop, so the assignment is a constant factor that I've chosen to exclude.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^2: Efficient bit-twiddling in Perl. by BrowserUk
in thread Efficient bit-twiddling in Perl. by BrowserUk

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


"be consistent"
	PerlMonks